Field of the Invention
The disclosure relates to a tube pump that delivers fluid and a fluid delivery method.
Description of the Related Art
In a conventionally known tube pump, a pressing portion such as a pressure roller that presses a tube is provided for a rotation body, i.e. a rotor, rotated by a drive unit such as a motor, and the pressing portion is moved by rotating the rotation body, thereby delivering or conveying fluid. In the tube pump constituted as above, there has been a problem that, if the pump is stopped for a long time, an area of the tube pressed by the pressing portion becomes difficult to be restored and to perform a function of sucking fluid from a delivery source side, i.e. a self-suction function.
Patent Literature 1 below, for instance, discloses a tube pump constituted in such a manner that an adhesion-state prevention member such as a linear member or a belt-like member is inserted into a tube for estranging inner surfaces of an occluded portion of the tube caused by pressure of a pressure member after removing pressure force.
Patent Literature 2 below discloses a tube pump in which a guide plate rotating integrally with a pump drive shaft has a function to release a pressure state of a tube by a pressure roller when it is not in use. The tube pump is constituted in such a manner that the guide plate is provided with a guide hole in a long hole shape which movably retains the pressure roller in a tube pressure state or in a released state and, when it is not in use, the pressure roller is moved along the guide hole by reversely rotating the pump drive shaft, thereby becoming the pressure released state.